Estimation of the effects of climate change scenarios on future Rhine water temperature development

The International Commission for the Protection of the Rhine had established an expert group to estimate the future development of Rhine water temperatures from Basel to the Rhine Delta by using climate scenarios. This work had been carried out within the scope to analyse past and future changes in river discharge and water temperature and their impact on ecosystem behaviour. The foundings were used to consider if any possible actions where needed to deal with the emerging and future impacts. This expert group made use of available models to make estimations for the time horizon 2021 - 2050 and 2071 - 2100. The expert group concluded that water temperatures will increase in the near future with about 1˚C – 1.5˚C and in the far future with about 3˚C – 3.5˚C. The difference in river discharge barely has a significant impact on water temperature. The expert group also concluded that the extreme conditions of August 2003 will be an average summer situation in the far future.